Document -config=<file> command line option

doc.html

@@ -349,6 +349,15 @@
                         <td>-nocolor</td>
                         <td>Turn off colored stdout/stderr.</td>
                     </tr>
+                    <tr>
+                        <td>-config=&lt;file&gt;</td>
+                        <td>
+                            Supply a configuration file to set options.
+                            Note: If a file named <b>gmqcc.ini</b> or
+                            <b>gmqcc.cfg</b> is found it will be loaded
+                            implicitally.
+                        </td>
+                    </tr>
                 </table>
                 
                 <h1><a name="bdoc">Building Documentation</a></h1>